Variable condenser



' Feb. 2 1926 1,571,370

(5. H. CLARK VARIABLE CONDENSER Filed March 5, 1921 g2 Ill 5 1s 12 10 22 z Patented Feb. 2, 1926.

UNITED STATES GEORGE HOWARD CLARK, 0F BROOKLYN, NEW YORK, ASSIGNOR TORADIO CORPORA- TION OF AMERICA, A CORPORATION 015 DELAWARE.

VARIABLE CONDENSER.

Application filed March 3, 1921. Serial No. 449,393.

To all whom it may concern:

Be it known that I, GEORGE H. CLARK, a citizen of the'United States, anda resident of Brooklyn, New York, have invented certain new and usefulImprovements in Variable Condensers, of which the following nailing,consists of two sets of flat semi-circular plates, one set being fixedand the other set rotatable between the fixed plates, so that segmentsof each set of varying area are placed in juxtaposition. With this typeof condenser the. minimum capacity is arbitrarily calculated at 10 andthe maximum at 170. The ratio of maximum to minimum for these values isabout 17 to 1.

My invention aims to increase the ratio of maximum to minimum and theactual range of capacity with this type of condenser. However theinvention is not necessarily limited thereto, although for convenienceit will be described in this connection.

The novel features which I believe to be characteristic of my inventionare particularly set forth in the appended claims, the

invention itself, however, both as to its construction and mode ofoperation, together with further objects and advantages thereof, willbest be understood by reference to the following description taken inconnection with the accompanying drawings, in which:

Fig. 1 is a section of a variable condenser embodying my invention andFig. '2 is a section on the line A--A of Fig. 1.

The objects referred to are secured by providing a construction in whichthe distance between the plates, as well as the cooperating overlappingsurfaces of the condenser is adapted to be varied to change thecapacity. A desirable arrangement for accomplishing this result, asillustrated byway of example in the drawings, comprises-a casing 1having a plurality of semi-circular metal plates 2 in the lower partspaced equidistant and electrically connected, for example by means of arod 3, passing through lugs 4, which extend into thereof, which are thebottom of the casing. In the upper part of the casing a similar set ofsemi-circular plates 5, is located, the plates being fastened to therotatable shaft 6 and spaced about the same distance as the plates ofthe first set. One end 7 of the shaft is screw threaded and adapted tofit in a cup shaped bushing 8 and the other end 9 is fitted in anotherbushing 10 and keyed to the stud 11 of a knob 12 made of insulatingmaterial. A stop 13 is provided to limit the sidewise movement of theplates when the shaft is rotated. The end of the casing is provided witha dial 14 and an indicator 15 cooperating therewith is attached to theshaft 6.

With the arrangement described it is pref erable to space the plates sothat when the rotatable plates are turned into the upper most positionas shown in Fig. 2, the planes of the plates of one set are intermediateand equidistant from the planes of the plates of the other set. In thetype of condenser referred to previously, this relative position ismaintained when the upper set of plates is rotated to vary the capacity.According to the invention as illustrated in the arrange ment shown, thespacing between the plates is changed as the overlapping is varied. Thescrew threaded rod and bushing, which is merely a convenient cam actionfor this purpose, draws the plates toward the right during the rotation.so that when the plates are rotated through 180, the' end of the shaftabuts against the bottom of the cup shaped bushing. This brings theplanes of one set of plates gradually closer to the planes of the otherset of plates.

With a plurality of plates in each set this, of course, draws the platesnearer to one cooperating plate and further from the other, whichincreases the capacity between. the close plates and decreases thecapacity between the distant plates as compared with equidistant plates.However, it can be shown that an increase of capacity is secured in thismanner, as the proportional in crease is greater than the decreasereferred to v I have found when my invention is applied to a condenserof the type having a set of rotatable semi-circular plates and a set ofstationary plates, ordinarily having a maximum to minimum ratio of 17 to1, that this can readily be increased to 30 to 1 by means of myinvention. With plates .03"

Bill

apart this result can be secured by moving the rotatable plates so thatthey are .01" from the close fixed plates. The actual capacity and therange is thus increased substantially 75%. This increased capacity willalso permit the use of a condenser .hav-

ing smaller or less plates .for the same purpose, and will give a betterratio. of maximum to minimum.

Having described my invention what I claim is 1. A variable electricalcondenser, comprising spaced juxtaposed fiat and parallel surfacesadjustable as to the area of the surfaces in juxtaposition and as tothedis- .tance between the surfaces by manipulation prising a pair ofspaced fiat and substanlially parallel condenser plates, one of saidplates being fixed and the other mounted on a shaft and slidably androtatably adjustable relative to the fixed plate, and means for varyingthe distance between said plates by manipulation of said shaft.

4. A variable electrical condenser comprising a pair of spaced-flat andsubstanti'ally parallel condenser plates, one of said plates beingfixedand the other mounted on a shaft and rotatable to vary the overlappingsurfaces, and means for varying the distance between said plates bymanipulation of said shaft. 4

4 5. A variable electrical condenser comprising' a pair of spaced flatand substantially parallel condenser plates, one of said plates beingfixed, mleans for rotating the other plate about an axis to vary theoverlapping surfaces and means cooperating with the rotating means forsimultaneously" varying the distance between said plates.

6. A variable electrical condenser comprising a set of spaced flatcondenser plates,

a second set of spaced fiat condenser plates amounted on a shaft to beslidably and rotatably adjustable between the first set and means forvarying the effective separation .of the plates by manipulation of saidshaft.

7. A variable electrical condenser comprising a set of fixed equidistantflat condenser plates, a second set of equidistant flat condenser platesmounted on a shaft and slidably and rotatably adjustable between theplates of the first set and means for moving one set of plates laterallyby manipulation of said shaft to vary the effective spacing of theplates of the condenser.

8. A variable electrical condenser, comprising a set of fixed condenserplates, a set of semi-circular plates, rotatable between the plates ofthe first set, means for rotating said plates, means for longitudinallymoving the axis of rotation of the second set by manipulation of saidfirst named means to vary the effective se aration of the plates.

9. A. variab e electrical condenser comprising a set of fixedcondenserplates, a shaft having a second set of condenser plates attachedthereto, and movable between the plates of the first set, said shaftbeing rotatable to vary the oi'erlapping surfaces, and means cooperatingwith said shaft for moving one of the sets longitudinally in relation tothe other set by manipulation of said shaft.

10. A variable electrical condenser comprising a set of fixed condenserplates, a shaft having a second set of condenser plates attached theretoand movable between the plates of the first set, said shaft being r0-tatable to vary the overlapping surfaces, 8. support for said shaft andmeans cooperating with said support for mloving the shaft longitudinallyduring said rotation.

1.1. A Variable electrical condenser comprising a set of. fixedcondenser plates, a

shaft having a sepond set of condenser plates attached thereto andadapted to rotate the attached plates between the fixed plates and asupport for said shaft, said shaft and support being threaded to producelongitudinal movement of the shaft during its rotation.

GEORGE HOWARD CLARK.

